Conceptual model of sediment processes in the upper Yuba River watershed, Sierra Nevada, CA

Abstract

This study examines the development of a conceptual model of sediment processes in the upper Yuba River watershed; and we hypothesize how components of the conceptual model may be spatially distributed using a geographical information system (GIS). The conceptual model illustrates key processes controlling sediment dynamics in the upper Yuba River watershed and was tested and revised using field measurements, aerial photography, and low elevation videography. Field reconnaissance included mass wasting and channel storage inventories, assessment of annual channel change in upland tributaries, and evaluation of the relative importance of sediment sources and transport processes. Hillslope erosion rates throughout the study area are relatively low when compared to more rapidly eroding landscapes such as the Pacific Northwest and notable hillslope sediment sources include highly erodible andesitic mudflows, serpentinized ultramafics, and unvegetated hydraulic mine pits. Mass wasting dominates surface erosion on the hillslopes; however, erosion of stored channel sediment is the primary contributor to annual sediment yield. We used GIS to spatially distribute the components of the conceptual model and created hillslope erosion potential and channel storage models. The GIS models exemplify the conceptual model in that landscapes with low potential evapotranspiration, sparse vegetation, steep slopes, erodible geology and soils, and high road densities display the greatest hillslope erosion potential and channel storage increases with increasing stream order. In-channel storage in upland tributaries impacted by hydraulic mining is an exception. Reworking of stored hydraulic mining sediment in low-order tributaries continues to elevate upper Yuba River sediment yields. Finally, we propose that spatially distributing the components of a conceptual model in a GIS framework provides a guide for developing more detailed sediment budgets or numerical models making it an inexpensive way to develop a roadmap for understanding sediment dynamics at a watershed scale. Published by Elsevier B.V.

Effects of placer mining on suspended sediment budget: case study of north of Russia’s Kamchatka Peninsula

“…Observed rates in these surfacemined catchments are similar to rates reported from other regions of the world (West and Wali 1999, Bartley et al 2004, Makhinov and Makhinova 2006, Memarian et al 2012. They are in the range of estimates of annual sediment production from mass wasting in the Pacific region (Curtis et al 2005). Erosion rates for the northwest United States range from 9 to 72 m 3 km -2 year -1 for forested watersheds and from 22 to 3500 m 3 km -2 year -1 for logged and roaded watersheds (Roberts and Church 1986).…”

“…It is recognized that the dispersal, storage, and remobilization of sediment-associated metals in the fluvial system can be directly related to sediment-transport processes. The transformation of an entire fluvial system through the input of mining material has been documented (Curtis et al 2005). A few studies have aimed at quantitative understanding of the complicated interaction between flow, sediment transport, and morphological evolution in areas of sediment mining (Cao andGareth 2004, Chalov 2008).…”

Automated catena‐based discretization of landscapes for the derivation of hydrological modelling units

“…For hillslope erosion, some authors tried to quantify the relative importance of multiple process factors (e.g. Curtis et al 2005, Schoorl et al 2004. Scherrer & Naef (2003) classified various soil and terrain attributes according to their role for runoff generation processes.…”

Yuba River analysis aims to aid spring-run chinook salmon habitat rehabilitation

“…During the Gold Rush (mid-to late 19th century), hillsides were hydraulically mined until the practice was outlawed in 1884. In the absence of dams, vast hillside-mining sediments -about 684 million cubic yards (522 million cubic meters) -moved freely down the river network filling in valleys, smothering aquatic habitat and deterring salmon from entering the system (Curtis et al 2005). At the time, salmonid populations had plenty of alternative rivers in California to use to survive this localized disturbance.…”